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The Laryngoscope V C 2016 The American Laryngological, Rhinological and Otological Society, Inc.

Systematic Review

Postinflammatory Medial Canal Fibrosis: An Institutional Review and Meta-Analysis of Short- and Long-Term Outcomes

Robert G. Keller, MD; Adrian A. Ong, MD; Shaun A. Nguyen, MD, MA; Brendan P. O’Connell, MD; Paul R. Lambert, MD

Objective: Few studies report outcomes of surgical management of postinflammatory medial canal fibrosis (PIMCF). The objectives were to compare short- and long-term outcomes after surgical repair of PIMCF at our institution and systematically aggregate published data for meta-analysis. Data Sources: Medical records for the case series; PubMed, Scopus, and OVID/Medline for the systematic review/meta analysis. Methods: Patients undergoing surgical treatment of PIMCF were identified. Short-term ( < 2 years) and long-term ( > 2 years) postoperative outcomes were evaluated for the case series and aggregated for the meta-analysis. Results: At our institution, 16 patients (21 ears) were identified. Compared to the preoperative air-bone gap (ABG) (27.7 6 7.5 dB), mean postoperative short-term ABG (8.2 6 7.5 dB) and long-term ABG (15.3 6 11.3 dB) were significantly improved ( P < 0.001 for both). Although short-term restenosis rate was low (0%) among long-term follow-up patients, 64% (9 of 14) experienced some degree of recurrent canal narrowing, including one case of complete restenosis (7%). Similarly, meta-analysis pooled preoperative ABG (29.3 6 9.7 dB, 95% confidence interval [CI] 27.0–31.6) improved significantly during short-term (11.4 6 8.0 dB, 95% CI 8.3–4.5, P < 0.0001) and long-term (14.3 6 9.6 dB, 95% CI 11.6–16.9, P 5 0.0004) follow-ups, with partial deterioration in hearing over time. Long-term complete restenosis rate (13.8%) was worse than short-term (8.0%), with no significant difference over time ( P 5 0.85). Conclusion: Postinflammatory medial canal fibrosis is a rare condition that can successfully be treated with surgery to restore patency of the external auditory canal. Patients who experience improved hearing early on, however, are at significant risk of restenosis and recurrence of their conductive hearing loss with time. Key Words: Medial canal fibrosis, external auditory canal, air-bone gap, stenosis, canaloplasty. Level of Evidence: N/A. Laryngoscope , 127:488–495, 2017

canal (EAC), 1,2 chronic stenosing external otitis, 3 canal ste nosis, 4 and obliterative otitis externa, 5 is thought to result from a variety of pathoetiologies including traumatic, post radiation, postinflammatory, iatrogenic, and idiopathic causes. Postinflammatory MCF (PIMCF) is the most com mon subtype, accounting for > 50% of cases, 6,7 and occurs as a complication of chronic or recurrent suppurative otitis media (CSOM), otitis externa (OE), or other inflammatory/ dermatologic conditions affecting the EAC. Although the pathophysiology of PIMCF is still not ful ly understood, it is generally felt that chronic inflammation leads to loss of the epithelial layer of the tympanic mem brane (TM) and subsequent formation of immature granula tions on the fibrous layer. 1,8,9 These granulations undergo fibrous degeneration; in the presence of persistent inflam mation, further deposition of granulations and fibrosis leads to the formation of a fibrous plug that progressively fills the EAC. This process characterizes the wet phase of the PIMCF cycle because recurrent otorrhea is common. Eventually, the fibrotic plug reaches the bony-cartilaginous junction; epithe lization may occur, resulting in a blind-ended EAC. At this point, bouts of OE cease to occur; the dry phase commences; and a conductive hearing loss (CHL) results. 1

INTRODUCTION Medial canal fibrosis (MCF) is a rare condition that often poses a diagnostic and therapeutic challenge to treat ing physicians. Historically confusing nomenclature and a lack of standardized definition of MCF have contributed to the difficulty in reaching a consensus regarding optimal management of this disease. Medial canal fibrosis, also referred to as acquired atresia of the external auditory From the Department of Otolaryngology–Head and Neck Surgery, Medical University of South Carolina ( R . G . K ., A . A . O ., S . A . N ., P . R . L .) Charles ton, South Carolina; and the Department of Otolaryngology–Head and Neck Surgery, Vanderbilt University Medical Center ( B . P . O ’ C .) Nashville, Tennessee, U.S.A. Editor’s Note: This Manuscript was accepted for publication July 6, 2016. Presented as an oral presentation at the 2016 Triological Society Annual Meeting at the Combined Otolaryngology Spring Meetings, Chicago, Illinois, U.S.A., May 20–21, 2016. Financial Disclosures: The authors have no funding, financial rela tionships, or conflicts of interest to disclose. Send correspondence to Robert G. Keller, MD, Department of Otolaryngology–Head and Neck Surgery, Medical University of South Carolina, 135 Rutledge Avenue, MSC 550, Charleston, SC 29425. E-mail: kelro@musc.edu

DOI: 10.1002/lary.26214

Laryngoscope 127: February 2017

Keller et al.: Retrospective Review and Meta-Analysis

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